Combination lock

ABSTRACT

A combination lock has a pair of toothed tumbler disks which are rotatably mounted on a slide. The slide is displaceable to bring the disks alternatively toward a pair of detents. Engagement between teeth of a disk and a detent produces rotation of the engaged disk. The disks have a pair of notches which, when aligned, allow the lock to be opened. The notches are initially offset, with a first of the disks being rotated relative to the second disk during prescribed maneuvering of the slide to bring about an alignment of the notches. The tip diameter of the second disk is smaller than the root diameter of the second disk. At selected points along the second disk the teeth have sunken recesses such that a detent entering such recess, in response to an incorrect manuevering of the slide, will engage the teeth of the second disk and rotate the second disk from its initial position. This eliminates all chances of the notches becoming properly aligned for unlocking.

United States Patent 1 [1 1 Norremark [451 Apr. 2, 1974 COMBINATION LOCK [76] Inventor: Christian Albert Norremark, Sdr.

Hostrup, DK-6200 Abenra, Denmark [22] Filed: May 9, 1972 [21] Appl. No.: 251,782

[52] US. Cl 70/313, 70/323, 70/333 R [51] Int. Cl... E05b 37/00 [58] Field of Search 70/301, 304, 306, 313, Y

[56] References Cited UNITED STATES PATENTS 3,209,566 10/1965 Norremark 70/304 3,602,021 8/1971 Martins 70/313 FOREIGN PATENTS OR APPLICATIONS 1,122,012 8/1956 France 70/304 Primary Examiner-Albert G. Craig, Jr. v Attorney, Agent, or Firm-Bums, Doane, Swecker & Mathis [57] ABSTRACT A combination lock has a pairof toothed tumbler disks which are rotatably mounted on a slide. The

' slide is displaceable to bring the disks alternatively toward a pair of detents. Engagement between teeth of a disk and a detent produces rotation of the engaged disk. The disks have a pair of notches which, when aligned, allow the lock to be opened. The

notches are initially offset, with a first of the disks being rotated relative to the second disk during prescribed maneuvering of the slide tobring about an alignment of the notches. The tip diameter of the second disk is smaller than the root diameter of the second disk. At selected points along the second disk the teeth have sunken recesses such that a detent entering such recess, in response to an incorrect manuevering of the slide, will engage the teeth of. the second disk and rotate the second disk from its initial position. This eliminates all chances of the notches becoming properly aligned for unlocking.

3 Chime T fie F re PATENIEDAPR 21914 3.800.577

sum 1 nr 2 Elsi . PRIOR ART fish-L- PRIOR ART PATENTEDAPR 219m SHEET 2 (IF 2 FIG? COMBINATION LOCK BACKGROUND AND OBJECTS OF THE INVENTION The present invention relates to a combination lock with two, toothed tumbler disks. The disks are rotatably mounted on a slide, the disks being able, by displacement of the slide in two mutually opposite directions, to be put into mesh with detents for stepwise advancement. An unlocking pawl is provided which, after operation of the lock in accordance with a predetermined combination, can be received in oppositely disposed notches of the tumbler disks.

Such a combination lockis known, e.g., from the specification of the U.S. Pat. No. 3,209,566, in which the teeth of the row of teeth of one of the tumbler disks are omitted at certain positions, such positions being located at point where a combination requires displacement of the slide in a direction opposite to the omitted tooth, portions. The other tumbler disk has its rows of teeth intact.

In such a combination lock, displacement of the slide in accordance with the combination causes both tumbler disks to be moved forward, while a displacement thereof in disaccord with the combination causes only 7 the other tumbler disks, i.e., having intact rows of teeth, to be moved forward. In the latter instance, the two tumbler disks will thus be displaced in relation to each other and can no longer beput into the correct mutual position, i.e., wherein the notch of one of the disks is disposed opposite to that of the other disk. When the slide is correctly displacedaccording to the combination, the two notches will be located in front of, and will receive, the unlocking pawl. The unlocking pawl may, for instance, be actuated by a spring such that in this condition the lock will be released.

As mentioned, the tumbler disk with intact rows of teeth is advanced by every sideways operation of the slide. To assure that the tumbler disk having non-intact rows of teeth is not moved by the other tumbler disk, the momentum of friction between the non-intact tumbler disks and associated contacting collar of an operating pin must be greater than that between the intact tumbler disks and an associated contacting collar on the operating pin. In other words, the momentum of friction relative to the two collars in question will be greater for the non-intact tumbler disks. Moreover,

both momenta of friction must be so small that the disks can be safety advanced by the detents, but must be great enough that the disks are not reversed when the rows of teeth are placed out of mesh with the detents. When making such a lock it is difficult to control these different amounts of friction correctly. To ensure that the desired effects will be achieved, the frictions have been made so heavy that the lock may be difficult to operate. Besides, the friction conditions may change as the result of wear and tear and the influx of dirt while the lock is in use.

The difficulties of controlling the amounts of friction are increased because it has proven to be necessary to use a so-called lock washer which must be advanced and reversed by friction of the intact tumbler disks, i.e., the disks which are always advanced during operation.

The lock washer is of smaller diameter than the tumbler disks and has a projection which retains the locking pawl when the lock is in its initial position. By displacement of the slide, the projection of the lock washer is cancelled from the retaining position as a result of the lock washer being moved by the intact tumbler disks.

If the slide is displaced so many times that the tumbler disks are carried to their end positions, the notches of the disks will again be in the correct position, i.e., mutually opposite to each other. At the same time, the projection of the lock washer will be located in front of these notches. Due to this location of the lock washer, it will be impossible to open the lock during cancellation. During cancellation, the two tumbler disks are led back to their initial position, during which time the notches are located relatively opposite one another. If the projection of the lock washer did not follow the notches, the unlocking pawl could, by the passage of the notches during cancellation, be received in the notches and thereby cause release of the lock.

An object of the present invention is to provide a combination lock of the type in question, in which it is unnecessary to use a lock washer.

BRIEF SUMMARY OF A PREFERRED EMBODIMENT This is achieved in accordance'with the invention, in that the diameter of the tip circle of one tumbler disk is smaller than the diameter of the root circle of the other disk. The tooth spacing in the row of teeth of the larger tumbler disk is sunk, i.e., recessed, at the positions where the combination requires displacement in an opposite direction. The notch of the smaller tumbler disk is located opposite to the unlocking pawl in the initial position of thelock.

During correct operation of the lock, displacement of the'slide in accordance with the combination causes only the larger tumbler disks to be advanced. The initial position of the smaller disks constitutes the opening, i.e., unlocking, position of these disks. If the lock is not operated in accordance with the prescribed combination, the smaller disk is shifted away from its unlocking position and can be'returned thereto only by cancellation.

Since the releasenotches of the disk are not positioned opposite to each other in either the initial position or in the end position, the lock can not be released during cancellation.

THE DRAWINGS The invention "will now be further explained in detail below with reference to the drawings, in which:

FIG. 1 shows the essential parts of a combination lock of the type in question,

FIG. 2 shows two tumbler disks and a lock washer of a known lock,

FIG. 3 shows the two tumbler disks of the lock according to the invention.

FIG. 4'is an elevational view of an embodiment of a code lock, according to the invention, viewed from the front;

FIG. 5 is an elevational view of the lock seen from behind,

FIG. 6 is an elevational view of a slide incorporated in the lock with the disks of the tumbler code unit, seen from behind; and

FIG. 7 is a vertical section through the lock according to the line 77 in FIG. 4.

DETAILED DESCRIPTION OF PRIOR ART I The two toothed and equally big tumbler disks 1] and 12 for the known lock are shown in FIG. 2. By displacement of the slide 1 the teeth and 16, respectively, of the two tumbler disks 11 and 12 are placed into mesh with the detents 2 for stepwise counterclockwise advance. The matches 13 and 14 of these disks are, in the initial disk position (shown in FIG. 2) located opposite to each other. If the lock is operated in accordance with the. prescribed combination, the two disks 1 l and 12 are moved simultaneously, so that the notches l3 and 14, after a certain number of advancements of the disks, will be located opposite to each other in the releasing position of the lock. In this releasing position locking pawl 3 can be received within the notches to thereby release the lock.

In the tumbler disks 11 some teeth are left out, i.e., omitted so that there will be an extra tooth space 17 located in a predetermined position depending upon the combination to be used. When a detent has advanced the disk 11 so as to rest against a tooth immediately preceding such a space 17, a subsequent movement of the slide in the same direction will only produce advancement by this detent of the tumbler disks 12, the latter having intact teeth. In this fashion, the combination is cancelled, because the notches l3 and 14 of the two disks are no longer opposite one another.

On the spindle of the tumbler disks there is in the known lock, one more disk, namely, a lock washer 4. In the initial position of the two tumbler disks, a projection 5 on the lock washer 4 retains the unlocking pawl. As soon as the lock is operated, however, the lock washer 4 is frictionally moved by the tumbler disk 12 so as to release the unlocking pawl. The lock washer acts as follows:

When operating the lock in a non-unlocking sequence, the tumbler disks both pass-by the unlocking position and the two notches will eventually become located opposite to each other. When the lock is cancelled, thetwo tumbler disks are reversed and the lock washer is frictionally moved so as to retain the unlocking pawl before the two notches pass the unlocking pawl in an unlocking position. If this was not the case, the lock could be opened by a person not knowing the combination. Such a person could cause the tumbler disks to pass-by the opening position to the end position and then cancel the lock cautiously and slowly so that the unlocking pawl could, during this reverse movement, slide into the two notches as they pass-by.

As previously noted, the use of a lock washer increases the difficulties of getting corrected frictions, since the lock washer must be frictionally moved in two directions by the tumbler disc 12.

It is required that friction between the disks 11 and 12 be of such a nature that the disk 12 cannot frictionally move the disk 11. This is achieved by the known lock in that the momentum of friction between the nonintact disk and an associated collar on the spindle is greater than the momentum of friction between the intact disk 12 and its corresponding collar. Both momenta of friction must, however, be small enough that the detents 2 can advance the disks, and large enough so that the disks are not reversed when the teeth are placed out of mesh with the detents.

.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION the disk 21 is smaller than the diameter of the root cir- I cle of the teeth 26 of the disk 22. In this fashion, the disk 22 can be advanced by the detents without the disk 21 being moved. The tooth spacing of the disk 22 is sunk, or recessed, at positions wherein the combination requires displacement of the slide in a direction opposite to such positions.

In the initial position of the disks 21 and 22, shown in FIG. 3, the notches 23 and 24, respectively, of the disks are not located opposite to each other, because the notch 23 of the disk 21 is, in its initial position, in the unlocking position. If the lock is operated in accor dance with the prescribed combination, the tumbler disk 21 shall not be moved.

If the lock is operated in disaccord with the combination, one of the detents 2 will be received within a recessed tooth space 28 of the disk 22, and will thereby be placed into mesh with the teeth 25 of the disk 21. As a result, the disk 21 will be moved from its initial position which, as mentioned, is also the unlocking position. In the end position, i.e., when the tumbler disks have been advanced as far as possible, the two notches are located in mutually displaced positions as in the initial position. When the lock is cancelled, the notches of the two disks will not pass the locking pawl simultaneously, and thus it is unnecessary to use a lock washer as in the known lock.

The operation of the disks 21 and 22 will be described subsequently in connection with a lock mechanism arranged in accordance with principles taught by the inventors US. Pat. No. 3,209,566.

The lock mechanism illustrated in FIGS. 4 through 7 comprises a lock casing consisting of a front plate 30 and side walls 32 and 33 constructed in one piece with the front plate, and a rear plate 34. The front plate has an opening which is substantially shaped as a rectangle 35 having an upper narrower part 36 and a vertically extending slot 37 at the top and 38 at the bottom. Immediately behind the openings 35, 36, 37, 38 in the front plate there is arranged a guide plate 39 having a bent edge 40 which extends into the opening in the front plate and by means of a screw spring 41 mounted in the slot 38 normally is kept in abutment against the lower edge of the rectangular part 35 of said opening. The guide plate may, by the tension of the spring 41, be displaced upwards along the front plate 30'as well as tilted to one or the other side, whereby the corresponding end of its bent edge 40, in abutment against the lower edge of the rectangular part 35 of the opening in the front plate, acts as a fulcrum. The guide plate 39 has a vertical slot 42 which in the normal position flushes with the vertical slot 37 in the front plate.

Behind the guide plate 39 there is a maneuvering slide 43 which is displaceable in the vertical direction in the lock casing. The maneuvering slide 43 rests on two pressed up ribs 44 on the front plate 30 and is provided with bent side pieces 45 gliding against the inner side of the side walls 32 and 33 of the lock. The maneuvering slide has a big rectangular cut-out 46. Behind the latter there is a setting slide 47 which is horizontally displaceably mounted on the maneuvering slide 43. The setting slide carries a through pin or shaft 48..It extends forward through the cut-out 46 in the maneuvering slide, the slot 42 in the guide plate 39 and the opening in the front plate 30 of the lock casing, and serves for the setting and maneuvering of the lock and may in front of the front plate be provided with a maneuvering knob (not shown). The pin 48 continues behind the setting slide 47 and carries at this place the two rotatable code-discs 21 and 22. The innermost of said code discs 21 rests against an annular flange 51 on the guide slide 47, while the outermost code disc 22 abuts against a shoulder 52 on the end of the inwardly extending portion of the pin 48. Between the two tumbler discs is inserted a domed spring disc 53 (FIG. 7) placing the code discs under tension between the annular flange 51 and the shoulder 52. Therefore, rotation in relation to the pin 18 can only be performed when overcoming a counteracting frictional effect. This is greater as far as the innermost tumbler code disc 21 is concerned, because the frictional effect fromthe annular flange 51 acts on a greater radius than the frictional effect from the shoulder 52.

The side pieces 45 of the maneuvering slide 13 are fastened to resilient detents or pawls 54 and 55 for cooperation with teeth 25 on the code disc 21 and teeth 26 on the code disc 22. The cooperation between the pawls and the teeth will be described later below.

On the inner side of the rear plate 34 is arranged a horizontally displaceable release slide 62 having a bent tongue 63 extending out through a horizontal slot 64 in the rear plate and standing under the influence of a spring 65 mounted on the rear side of the rear plate. The release slide 62 has onits inner side a vertical cam 66 and an oblique cam 67 for cooperation with a backwardly extending nose 68 on the maneuvering slide 43.

On the rear side of the rear plate 34 is arranged a vertically displaceable blocking slide 69, standing under the influence of a spring 70. The blocking slide 69 has a bent tongue 71 which isdisplaceable in a slot 72 in the rear plate. On the edge facing the release slide 62 the blocking slide 69 has an incision 73 in cooperation with the tongue 63 of the release slide in a manner to be described further below.

The pawls 24 and 25 have such a width that they can cooperate simultaneously with both code discs.

The mode of operation of the lock as described in conjunction 'with FIGS. 4 through 7 is in accordance with the operation as previously described. Thus, in the initial position of the disks 21 and 22, shown in FIGS. 6, the notches 23 and 24, respectively, of the disks are not'located opposite to each other, because the notch 23 of the disk 21 is, in its initial position, in the unlocking position. If the lock is operated in accordance with the prescribed combination, the tumbler disk 21 shall not be moved.

If the lock is not operated in accordance with the combination, one of the detents 54, 55 will be received within a recessed tooth space 28 of the disk 22, and will thereby be placed into mesh with the teeth 25 of the disk 21. As a result, the disk 21 will be moved from its initial position which, as mentioned, is also the unlocking position. In the end position, i.e., when the tumbler disks have been advanced as far as possible, the two notches will be located in mutually displaced positions.

and cannot by any subsequent setting maneuver be brought into register again.

If the correct number of displacements are undertaken in the correct sequence from left to right, the two I notches 23 and 24 will become registered with each other and will at least both appear at a position vertically under the pin 48.

When the setting maneuver has been terminated, opening of the lock will be brought about by pressing the pin 48 downwards. By this operation the maneuvering slide 43 will as a unit move downwards.

Provided the notches 23 and 24 are in their correct position for opening the lock they will glide down over the tongue 71 of the blocking slide 69, and when the bottom of the notches reaches the tongue 71, the blocking slide 69 will be carried along downwards. At the same time the nose 68 of the maneuvering slide 43 will slide along the cam 66 of the release slide 62. When the nose 68 gets below the lower end of the cam 66, the release slide 62 will be released and try to slide to the right-hand side in FIG. 5 under the influence of the spring 65. This movement is possible if the notch 73 in the blocking slide 69 is located opposite the tongue 63 which will be the case when as mentioned above the tongue 71 has reached the bottoms in the notches 23 and 24 before the blocking slide 69 is carried along in the downward movement of the maneuvering slide 43.

' hand side.

The displacement of the release slide 62 towards the right-hand side may be utilized in any known manner for the opening of the lock. It can for instance displace a latch, close or interrupt an electric circuit, displace a solenoid core or any other locking member. The manner in which the release movement of the slide 62 is utilized for actuating such locking member does not form any part of the present invention.

The locking takes place by moving the pin 48 vertically upwards. By this operation the nose 68 of the maneuvering slide 43 hits the oblique cam 67 of the release slide 62 and will consequently move the release slide towards left in FIG. 5. At the same time the code discs 21 and 22 are moved free of the tongue 71 of the blocking slide 69 so that the blocking slide can move upwards under the influence of the spring 70. As soon as the tongue of the release slide 62 has moved free of the cutout 73, the blocking slide 69 will consequently be displaced in the upward direction in such a manner that the cut-out 73 will be displaced relative to the tongue 63 whereby the release slide 62 is blocked. By

a further upward movement of the pin 48 the two tongues 76 and 77 on the code disc 22 (FIG. 6) are brought into engagement with two cams 78 on the inner side of the rear plate 4 (FIG. 7). Thus the code disc is cleared.

A projection 79 on the code disc 21 extending through a cut-out 80 in the spring disc 53 and into a cut-out 81 in the code disc 22 will cause the code disc 21 to be carried along during the clearing movement of the codedisc 22. The projection 79 has so much play in the cut-out 51 that there is nothing to prevent a mutual displacement of the code discs during correct maneuvering.

The guide plate 39 serves to carry the pin 48 back to neutral position, irrespective of whether it has been displaced to the right or to the left or upwards in the slot 37. By a movement of the pin to the left or to the right the return movement takes place in the way that the guide plate is tilted back to vertical position whereby one of the side edges of the slot 42 presses on the pin 48. The return movement of the pin from vertically displaced position takes place by a vertically sliding movement of the guide plate whereby the upper edge of the slot 42 will press against the pin 48. In both instances it is one and the same spring, viz. the screw spring 41, that undertakes the return movement.

I claim:

1. In a combination lock of the type wherein a pair of toothed disks are rotatably mounted on a slide; the

. 8 slide being selectively displaceable in generally opposite directions to shift the disks toward meshing engagement with spaced detents, such meshing engagement being operable to advance the disks in stepwise rotation; the disks including notches which are alignable, in response to displacement of said slide in accordance with a predetermined combination, for the reception of an unlocking means in order to actuate an unlocking mechanism of the lock; the improvement wherein:

said disks are normally initially disposed such taht said notches are mutually offset, with the notch of a first of said disks being located opposite said unlocking means; the tip diameter of said first disk projecting no further than the root diameter of the second disk and unlocking means comprises an unlocking pawl. 

1. In a combination lock of the type wherein a pair of toothed disks are rotatably mounted on a slide; the slide being selectively displaceable in generally opposite directions to shift the disks toward meshing engagement with spaced detents, such meshing engagement being operable to advance the disks in stepwise rotation; the disks including notches which are alignable, in response to displacement of said slide in accordance with a predetermined combination, for the reception of an unlocking means in order to actuate an unlocking mechanism of the lock; the improvement wherein: said disks are normally initially disposed such taht said notches are mutually offset, with the notch of a first of said disks being located opposite said unlocking means; the tip diameter of said first disk projecting no further than the root diameter of the second disk and said second disk including sunken portions between selected teeth such that a detent, upon entering one such sunken portion in disaccord with the predetermined combination, meshingly engages a tooth of said first disk to advance the latter and shift the notch thereof ouT of alignment with said unlocking means.
 2. The apparatus according to claim 1 wherein the tip diameter of said first disk is less than the root diameter of the second disk.
 3. The apparatus according to claim 2 wherein said unlocking means comprises an unlocking pawl. 